21380716 has 12 divisors (see below), whose sum is σ = 42761488. Its totient is φ = 9163152.

The previous prime is 21380693. The next prime is 21380729. The reversal of 21380716 is 61708312.

21380716 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 763597 = 21380716 / (2 + 1 + 3 + 8 + 0 + 7 + 1 + 6).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 381771 + ... + 381826.

Almost surely, 2^21380716 is an apocalyptic number.

It is an amenable number.

21380716 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21380716 is a wasteful number, since it uses less digits than its factorization.

21380716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763608 (or 763606 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21380716 is about 4623.9286326672. The cubic root of 21380716 is about 277.5496910717.

The spelling of 21380716 in words is "twenty-one million, three hundred eighty thousand, seven hundred sixteen".